The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 10, 1989
Filed:
Jul. 08, 1986
Ernst Spietschka, Idstein, DE;
Manfred Urban, Wiesbaden, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for the preparation of perylene-3,4,9,10-tetracarboxylic acid N,N'-dimethylimide in a high-hiding pigmentary form and a pure red shade, in which a finely divided, dry perylene-3,4,9,10-tetracarboxylic acid, N,N'-dimethylimide prepigment which is prepared in a conventional manner and has a crystallite size of <400 .ANG. is treated with an organic solvent which is liquid in the treatment temperature range stated below and is selected from the series comprising saturated aliphatic brominated or chlorinated hydrocarbons, aromatic hydrocarbons and aromatic brominated or chlorinated hydrocarbons, in a mill or a disperser at temperatures from 0.degree. C. to 100.degree. C., the organic solvent is then distilled off and the perylene-3,4,9,10-tetracarboxylic acid N,N'-dimethylimide pigment is isolated.